FPGA-based Implementation of Signal Processing Systems Roger Woods Queen’s University, Belfast, UK John McAllister Queen’s University, Belfast, UK Gaye Lightbody University of Ulster, UK Ying Yi University of Edinburgh, UK A John Wiley and Sons, Ltd., Publication FPGA-based Implementation of Signal Processing Systems FPGA-based Implementation of Signal Processing Systems Roger Woods Queen’s University, Belfast, UK John McAllister Queen’s University, Belfast, UK Gaye Lightbody University of Ulster, UK Ying Yi University of Edinburgh, UK A John Wiley and Sons, Ltd., Publication This edition first published 2008 2008 John Wiley & Sons, Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com. The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Wood, Roger. FPGA-based implementation of complex signal processing systems / Roger Wood ... [et al.]. p. cm. Includes bibliographical references and index. ISBN 978-0-470-03009-7 (cloth) 1. Signal processing–Digital techniques. I. Title. TK5102.5.W68 2008 621.3822–dc22 2008035242 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. ISBN: 978-0-470-03009-7 Typeset by Laserwords Private Limited, Chennai, India Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire To Rose and Paddy Contents About the Authors xv Preface xvii 1 Introduction to Field-programmable Gate Arrays 1 1.1 Introduction 1 1.1.1 Field-programmable Gate Arrays 1 1.1.2 Programmability and DSP 3 1.2 A Short History of the Microchip 4 1.2.1 Technology Offerings 6 1.3 Influence of Programmability 7 1.4 Challenges of FPGAs 9 References 10 2 DSP Fundamentals 11 2.1 Introduction 11 2.2 DSP System Basics 12 2.3 DSP System Definitions 12 2.3.1 Sampling Rate 14 2.3.2 Latency and Pipelining 15 2.4 DSP Transforms 16 2.4.1 Fast Fourier Transform 16 2.4.2 Discrete Cosine Transform (DCT) 18 2.4.3 Wavelet Transform 19 2.4.4 Discrete Wavelet Transform 19 2.5 Filter Structures 20 2.5.1 Finite Impulse Response Filter 20 2.5.2 Correlation 23 2.5.3 Infinite Impulse Response Filter 23 2.5.4 Wave Digital Filters 24 2.6 Adaptive Filtering 27 2.7 Basics of Adaptive Filtering 27 2.7.1 Applications of Adaptive Filters 28 2.7.2 Adaptive Algorithms 30 viii Contents 2.7.3 LMS Algorithm 31 2.7.4 RLS Algorithm 32 2.8 Conclusions 35 References 35 3 Arithmetic Basics 37 3.1 Introduction 37 3.2 Number Systems 38 3.2.1 Number Representations 38 3.3 Fixed-point and Floating-point 41 3.3.1 Floating-point Representations 41 3.4 Arithmetic Operations 43 3.4.1 Adders and Subtracters 43 3.4.2 Multipliers 45 3.4.3 Division 47 3.4.4 Square Root 48 3.5 Fixed-point versus Floating-point 52 3.6 Conclusions 55 References 55 4 Technology Review 57 4.1 Introduction 57 4.2 Architecture and Programmability 58 4.3 DSP Functionality Characteristics 59 4.4 Processor Classification 61 4.5 Microprocessors 62 4.5.1 The ARM Microprocessor Architecture Family 63 4.6 DSP Microprocessors (DSPµs) 64 4.6.1 DSP Micro-operation 66 4.7 Parallel Machines 67 4.7.1 Systolic Arrays 67 4.7.2 SIMD Architectures 69 4.7.3 MIMD Architectures 73 4.8 Dedicated ASIC and FPGA Solutions 74 4.9 Conclusions 75 References 76 5 Current FPGA Technologies 77 5.1 Introduction 77 5.2 Toward FPGAs 78 5.2.1 Early FPGA Architectures 80 5.3 Altera FPGA Technologies 81 5.3.1 MAXr 7000 FPGA Technology 83 5.3.2 Stratixr III FPGA Family 85 5.3.3 Hardcopyr Structured ASIC Family 92 5.4 Xilinx FPGA Technologies 93 5.4.1 Xilinx VirtexTM -5 FPGA Technologies 94 Contents ix 5.5 Lattice FPGA Families 103 5.5.1 Latticer ispXPLD 5000MX Family 103 5.6 Actel FPGA Technologies 105 5.6.1 Actelr ProASICPLUS FPGA Technology 105 5.6.2 Actelr Antifuse SX FPGA Technology 106 5.7 Atmel FPGA Technologies 108 5.7.1 Atmelr AT40K FPGA Technologies 108 5.7.2 Reconfiguration of the Atmelr AT40K FPGA Technologies 109 5.8 General Thoughts on FPGA Technologies 110 References 110 6 Detailed FPGA Implementation Issues 111 6.1 Introduction 111 6.2 Various Forms of the LUT 112 6.3 Memory Availability 115 6.4 Fixed Coefficient Design Techniques 116 6.5 Distributed Arithmetic 117 6.6 Reduced Coefficient Multiplier 120 6.6.1 RCM Design Procedure 122 6.6.2 FPGA Multiplier Summary 125 6.7 Final Statements 125 References 125 7 Rapid DSP System Design Tools and Processes for FPGA 127 7.1 Introduction 127 7.2 The Evolution of FPGA System Design 128 7.2.1 Age 1: Custom Glue Logic 128 7.2.2 Age 2: Mid-density Logic 128 7.2.3 Age 3: Heterogeneous System-on-chip 129 7.3 Design Methodology Requirements for FPGA DSP 129 7.4 System Specification 129 7.4.1 Petri Nets 129 7.4.2 Process Networks (PN) and Dataflow 131 7.4.3 Embedded Multiprocessor Software Synthesis 132 7.4.4 GEDAE 132 7.5 IP Core Generation Tools for FPGA 133 7.5.1 Graphical IP Core Development Approaches 133 7.5.2 Synplify DSP 134 7.5.3 C-based Rapid IP Core Design 134 7.5.4 MATLABr -based Rapid IP Core Design 136 7.5.5 Other Rapid IP Core Design 136 7.6 System-level Design Tools for FPGA 137 7.6.1 Compaan 137 7.6.2 ESPAM 137 7.6.3 Daedalus 138 7.6.4 Koski 140 7.7 Conclusion 140 References 141 x Contents 8 Architecture Derivation for FPGA-based DSP Systems 143 8.1 Introduction 143 8.2 DSP Algorithm Characteristics 144 8.2.1 Further Characterization 145 8.3 DSP Algorithm Representations 148 8.3.1 SFG Descriptions 148 8.3.2 DFG Descriptions 149 8.4 Basics of Mapping DSP Systems onto FPGAs 149 8.4.1 Retiming 150 8.4.2 Cut-set Theorem 154 8.4.3 Application of Delay Scaling 155 8.4.4 Calculation of Pipelining Period 158 8.5 Parallel Operation 161 8.6 Hardware Sharing 163 8.6.1 Unfolding 163 8.6.2 Folding 165 8.7 Application to FPGA 169 8.8 Conclusions 169 References 169 9 The IRIS Behavioural Synthesis Tool 171 9.1 Introduction of Behavioural Synthesis Tools 172 9.2 IRIS Behavioural Synthesis Tool 173 9.2.1 Modular Design Procedure 174 9.3 IRIS Retiming 176 9.3.1 Realization of Retiming Routine in IRIS 177 9.4 Hierarchical Design Methodology 179 9.4.1 White Box Hierarchical Design Methodology 180 9.4.2 Automatic Implementation of Extracting Processor Models from Previously Syn- thesized Architecture 181 9.4.3 Hierarchical Circuit Implementation in IRIS 184 9.4.4 Calculation of Pipelining Period in Hierarchical Circuits 185 9.4.5 Retiming Technique in Hierarchical Circuits 188 9.5 Hardware Sharing Implementation (Scheduling Algorithm) for IRIS 190 9.6 Case Study: Adaptive Delayed Least-mean-squares Realization 199 9.6.1 High-speed Implementation 200 9.6.2 Hardware-shared Designs for Specific Performance 205 9.7 Conclusions 207 References 207 10 Complex DSP Core Design for FPGA 211 10.1 Motivation for Design for Reuse 212 10.2 Intellectual Property (IP) Cores 213 10.3 Evolution of IP Cores 215 10.3.1 Arithmetic Libraries 216 10.3.2 Fundamental DSP Functions 218 10.3.3 Complex DSP Functions 219 10.3.4 Future of IP Cores 219 Contents xi 10.4 Parameterizable (Soft) IP Cores 220 10.4.1 Identifying Design Components Suitable for Development as IP 222 10.4.2 Identifying Parameters for IP Cores 223 10.4.3 Development of Parameterizable Features Targeted to FPGA Technology 226 10.4.4 Application to a Simple FIR Filter 228 10.5 IP Core Integration 231 10.5.1 Design Issues 231 10.5.2 Interface Standardization and Quality Control Metrics 232 10.6 ADPCM IP Core Example 234 10.7 Current FPGA-based IP Cores 238 10.8 Summary 240 References 241 11 Model-based Design for Heterogeneous FPGA 243 11.1 Introduction 243 11.2 Dataflow Modelling and Rapid Implementation for FPGA DSP Systems 244 11.2.1 Synchronous Dataflow 245 11.2.2 Cyclo-static Dataflow 246 11.2.3 Multidimensional Synchronous Dataflow 246 11.2.4 Dataflow Heterogeneous System Prototyping 247 11.2.5 Partitioned Algorithm Implementation 247 11.3 Rapid Synthesis and Optimization of Embedded Software from DFGs 249 11.3.1 Graph-level Optimization 250 11.3.2 Graph Balancing Operation and Optimization 250 11.3.3 Clustering Operation and Optimization 251 11.3.4 Scheduling Operation and Optimization 253 11.3.5 Code Generation Operation and Optimization 253 11.3.6 DFG